1. Field of the Invention
This invention relates to a new fuel control device, such as for supplying gaseous fuel to a burner means of a cooking apparatus, and to a new fuel control system utilizing such a fuel control device as well as to a new method of making such a fuel control device.
2. Prior Art Statement
It is known to provide a fuel control device comprising a housing means having an inlet for being interconnected with a fuel source and an outlet for being interconnected to a main burner means, the housing means having a main valve seat between the inlet and the outlet and a thermostatically operated valve member for opening and closing the main valve seat, the housing means having an annular heater pilot valve seat surrounding the main valve seat and being opened and closed by the thermostatically operated valve member at the same time that the thermostatically operated valve member is opening and closing the main valve seat.
The flow through the heater pilot valve seat of such prior known control device is directed to a main burner pilot which governs main burner flow through the opening and closing of a safety valve. The mechanism of control is the heating of the hydraulic element of the safety valve by the pilot flame. The safety valve is actuated by the hydraulic element to open and permit main burner fluid flow in response to the pilot flow condition.
Also, see the Wantz et al, U.S. Pat. No. 3,167,250 and the Branson et al U.S. Pat. No. 3,989,064 for other fuel control devices having heater pilot valve seat means.
It is one feature of this invention to provide a new fuel control device for supplying fuel to a burner means and wherein a tendency to starve the heater pilot means of fuel at the time the safety valve means of the fuel control system opens is substantially eliminated.
In particular, it was found according to the teachings of this invention that when the thermostatically operated valve member of a fuel control device opens so as to permit fuel to flow to a heater pilot means, the subsequent opening of the safety valve seat and flow of fuel to the main burner causes a reduction in flow through the heater pilot seat. The pilot flame thus reduced becomes inadequate to keep the safety valve open and closure results. When closure occurs, flow to the heater pilot returns to the former level. The increased pilot flame opens the safety valve which again decreases the flow of fuel to the heater pilot. It can be seen that this condition of instability prevents proper operation of the main burner means.
However, it was found according to the teachings of this invention that an annular auxiliary fuel supply valve seat could be provided in the housing means of the fuel control device so as to surround the heater pilot valve seat and be supplied fuel from the inlet independently of the main valve seat so as to substantially prevent a reduction in the flow of fuel to the heater pilot means during the time the safety valve initially opens so that the heater pilot maintains its heater flame in an operative condition thereof.
For example, one embodiment of this invention provides a fuel control device comprising a housing means having an inlet for being interconnected with a fuel source and an outlet for being interconnected to a main burner means, the housing means having a main valve seat between the inlet and the outlet and a thermostatically operated valve member for opening and closing the main valve seat, the housing means having an annular heater pilot valve seat surrounding the main valve seat and being opened and closed by the thermostatically operated valve member at the same time that the thermostatically operated valve member is opening and closing the main valve seat, the housing means having an annular auxiliary fuel supply valve seat surrounding the heater pilot valve seat and being adapted to be opened and closed by the thermostatically operated valve member at the same time that the thermostatically operated valve member is opening and closing the main valve seat and the heater pilot valve seat, the housing means having passage means for interconnecting the inlet to the auxiliary fuel supply valve seat independently of the main valve seat.
Accordingly, it is an object of this invention to provide a new fuel control device having one or more of the novel features of this invention as set forth above or hereinafter shown or described.
Another object of this invention is to provide a new fuel control system utilizing such a fuel control device, the system of this invention having one or more of the novel features of this invention as set forth above or hereinafter shown or described.
Another object of this invention is to provide a new method for making such a fuel control device, the method of this invention having one or more of the novel features of this invention as set forth above or hereinafter shown or described.
Other objects, uses and advantages of this invention are apparent from a reading of this description which proceeds with reference to the accompanying drawings forming a part thereof and wherein: